Avoid leaks false positive in CoreBluetooth mock

Author: ksperling-apple

src/darwin/Framework/CHIPTests/TestHelpers/MTRMockCB.m

@@ -16,7 +16,6 @@
 
 #import "MTRMockCB.h"
 
-#import <CoreBluetooth/CoreBluetooth.h>
 #import <XCTest/XCTest.h>
 #import <objc/runtime.h>
 #import <os/log.h>
@@ -169,6 +168,8 @@ static void InterceptClassMethod(__strong os_block_t * inOutCleanup, Class cls,
         // inherited implementation; this is good enough for our purposes here.
         method_setImplementation(method, originalImp);
         imp_removeBlock(newImp); // otherwise the block might leak
+        (void)block; // keep an obvious reference to avoid `leaks` false positives before cleanup
+
         if (nextCleanup) {
             nextCleanup();
         }